The present invention relates to a method for the generation of a nearly monodispersed aerosol in a filter-testing penetrometer machine.
The present invention is superior to the previous method in that it employs an composition as a replacement for dioctyl phthalate, which is a suspected carcinogen. The composition utilized in this invention is manufactured by Henkel Corporation, Emery Group, 11501 Northlake Drive, P. O. Box 429557, Cincinnati, OH 45249. The composition has been identified as a thermally stable material of low toxicity. The composition is a poly-alpha olefin containing about 97-99% by volume of a poly-alpha olefin having a chain length of 20 carbon atoms and about 1-3% by volume of a poly-alpha olefin having a chain length of 30 carbon atoms. The term poly-alpha olefin in this case is also called a synthetic hydrocarbon 2 CST fluid. The CST refers to centistokes, a measure of viscosity. The number ahead of the CST fluid specifies the viscosity at 100%.
Recently, a new generation of smoke penetrometers has been developed which utilize the generation of cold smokes or cold aerosols. Cold smokes or aerosols can be generated by the process of cold atomization/vaporization, and controlled nucleated recondensation of a liquid. This process produces a nearly monodispersed smoke. These machines are used to test U.S. Army masks, respirators, filters and other personnel protection equipment.
A description of the equipment is given elsewhere in this disclosure. The acceptable operation of the composition utilized in this invention has been confirmed by extensive testing in our research facility at Aberdeen Proving Ground, using the cited smoke penetrometers.